1. Field of the Invention
The present invention relates to a laser printer forming an image by scanning a plurality of laser beams, and more particularly, to a laser scan unit assembly capable of adjusting the plurality of laser beams from a plurality of laser scan units to be parallel with each other when scanned onto a photosensitive body, and a laser printer having the same.
2. Description of the Related Art
Generally, a laser printer prints a predetermined image by forming the image on a photosensitive body using laser beams emitted from a laser scan unit, and then transferring the image onto paper. A particular type laser printer such as a color laser printer forms an electrostatic latent image on the photosensitive body by emitting a plurality of laser beams from a plurality of laser scan units. Since the plurality of laser scan units are disposed at predetermined intervals to be parallel with each other, the laser beams emitted from the laser scan units are formed on the photosensitive body at predetermined intervals in parallel and create an electrostatic latent image. The laser printer then develops the electrostatic latent image created on the photosensitive body with a developing agent and transfers the developed image onto paper.
In such a laser printer, laser beams emitted from the laser scan units may not be parallel to each other due to manufacturing tolerances of the parts or assembling error. If the plurality of laser beams are not parallel, each color may be mis-positioned, thereby impairing print quality.
In order to solve such a problem, conventionally, a laser scan unit assembly adjusts the plurality of laser beams by adjusting angles of the mirrors reflecting the laser beams. Since a mirror unit has a laser scan unit inside, a motor is provided to adjust the angle of the mirror. The laser beams are formed on the photosensitive body in parallel with each other by adjusting the angle of the mirrors with a control unit controlling the motor.
However, problems occur when adjusting mirrors using a motor. First, the interior temperature of the laser scan unit increases as the temperature of the motor increases when used for a long time, and therefore the life span of the laser scan unit is reduced. Second, manufacturing costs are increased because the motors and the motor control units are required. Finally, space to dispose the additional motor is required, thereby enlarging the size of the laser printer. Therefore, there has been a need for a laser scan unit assembly capable of adjusting a plurality of laser beams on a photosensitive body without having to use a motor.